chlorpromazine hydrochloride: clinical use

Prescribing considerations

• Consider its marked sedative, hypotensive, anticholinergic and anti-emetic effects, particularly in older, frail or dehydrated patients.
• Assess cardiac disease, rhythm history, stroke and venous-thromboembolism risk, epilepsy, Parkinsonism, diabetes, hepatic or renal impairment, and vulnerability to temperature dysregulation.
• Avoid abrupt withdrawal where possible because relapse, nausea, vomiting, insomnia and movement symptoms can occur.
• Advise about photosensitivity, alcohol avoidance, driving impairment, infection symptoms and serious skin or liver reactions.

Contraindications and cautions

• Shared contraindications include hypersensitivity, risk of angle-closure glaucoma, urethroprostatic urinary retention, previous agranulocytosis or relevant marrow suppression, dopaminergic antiparkinsonism treatment, breastfeeding, and concomitant citalopram or escitalopram.
• The selected syrup additionally lists coma, severe CNS depression, severe cardiovascular disease and a history of blood dyscrasia.
• The selected tablet additionally lists hypothyroidism, phaeochromocytoma and myasthenia gravis. Check the exact formulation's current SmPC before prescribing.

Monitoring

• Obtain an urgent full blood count for unexplained fever, sore throat or infection; regular blood-count monitoring is recommended.
• Assess ECG and electrolytes when cardiac or QT-prolongation risk factors are present, and monitor for arrhythmia symptoms.
• Monitor weight, clinically relevant glucose or lipid changes, blood pressure and movement adverse effects.
• Investigate possible hepatic injury promptly. Long-term treatment warrants regular haematological and ophthalmological review.
• For children, the tablet SmPC advises annual clinical assessment of learning capacity.

Clinical pharmacology

A phenothiazine antipsychotic that primarily blocks dopamine receptors and also has alpha-adrenergic and anticholinergic actions. It is absorbed orally, extensively protein-bound, widely distributed and hepatically metabolised, with urinary and biliary excretion of metabolites.

Formulation and product differences

• The selected film-coated tablet contains lactose and is essentially sodium-free.
• The selected syrup contains sucrose, sorbitol, propylene glycol, parabens and a small amount of ethanol; consider diabetes, dental health, hereditary fructose intolerance and excipient hypersensitivity.
• Clinical response and tolerability may differ after switching formulation; review the patient after any change.

Syrup

Route: Oral

Strengths: 25 mg/5 mL, 100 mg/5 mL

Tablet

Route: Oral

Strengths: 25 mg, 50 mg, 100 mg